Gantz/Heartwarming

Believe it or not, Gantz actually has a handful of scenes that are genuinely heartwarming.

A major one is at the end of the Oni alien arc, where several people sacrifice their freedom from Gantz to resurrect their's and Kurono's friends and allow Kurono to go free. Even Nishi gets brought back.
Pretty much any scene with Takeshi and Kaze, especially the one where Kaze finds out how Takeshi died, and where he engages the Osaka boss alien in unarmed combat after it wounds Takeshi.
The scene where after losing their memories, Tae and Kurono find their way back to each other.
The scene after Kurono's nightmare of what could've happened if he never knew Tae. Finding his girlfriend by him in bed, Kurono realizes how much she means to him. Aww...
For as monumental an asshole as Kurono is at first, he also seems to be the most human character. First he earns the most points in the dinosaur mission, by saving everyone on the team and killing more foes than the resident Ax Crazy Blood Knight, gaining the respect of literally everyone present. Then he turns down Reika to be with the girl he loves, despite the fact that Reika is rich, an idol, insanely attractive, and devoted to him. All it seemed to take to push him onto the right track was having people finally respect him/be grateful toward him.
"I did it! Just like I promised!" ~the salaryman from the Osaka team, who's gotten enough points by now to bring back Anzu.
In ch. 321, Tae is rescued from certain death by an older man while aboard the alien ship/planet/sewer/thing. That same man had been giving her rather...creepy looks earlier. When she finally works up the courage to ask why he saved her of all people, he says that he's a Lolicon. A short time later, as he lies dying, he reveals that his daughter had been killed the day before during the invasion...and that Tae looks a lot like her.
In ch. 351, the long awaited reunion of Tae and Kei. After experiencing so much hell during the Katastrophe arc, it's hard not to tear up seeing Kei burst in tears just from seeing Tae again. The alien woman's reactions to this make this moment all the more heartwarming and tearjerking at the same time.
Chapter 275, when Anzu tells Kato that she loves him.